The present invention relates to an electronic circuit unit mounting structure for an electronic equipment support which allows a number of electronic circuit units constituting electronic equipment to be directly mounted on the support.
Communications equipment or similar electronic equipment has been proposed which has a plurality of electronic circuit units each being implemented by a printed circuit board which carries a number of electronic parts therewith. The electronic circuit units are mounted on individual communications equipment casings having substantial mechanical strength, and then loaded one above another on an equipment support. Basically, each casing has a box-like configuration which is formed by mechanically connecting opposite side panels, a top panel, and a bottom panel. A mother board has a connector which mates with connectors of the individual circuit units, while a shelf has guide channels for mounting and holding the circuit units in a predetermined position in the casing. The mother board and shelf are received in the box-like casing. There also has been proposed a communications equipment casing which is configured to mount electronic circuit units on the upper and lower panels in order to reduce the number of structural parts needed. In any case, however, the casing is assembled by interconnecting a plurality of parts by using screws and rivets.
Communication equipment casings of the type described and equipment supports for mounting such casings are disclosed in, for example, British Patent Nos. 1,315,641 and 1,315,642, and "Konstruktionsmerkmale der Bauweise 7R (BW 7R)" by Wilhelm Faber et al, Tech. Mitt. AEG-TELEFUNKEN (1974), Beih, Trgerfrequeztechnik.
As stated above, a communications equipment support has traditionally been regarded as a simple framework for fixing a casing which is loaded with a number of electronic circuit units that constitute communications equipment. Such equipment supports are usually positioned side by side or back-to-back and, hence, the maintenance of communications equipment and the installation of extra equipment should preferably be accomplished only by the manipulations performed in front of the supports. In practice, however, each casing (whose depthwise dimension is 20 centimeters or so) has a substantial weight when loaded with a number of electronic circuit units. It is extremely difficult to fix such a heavy casing surely to the equipment support by manipulating it in front of the support only. Since the structure of the casing as well as the procedure for fixing the casing in place is complicated and since the equipment support itself has to be provided with substantial mechanical strength, the support is disproportionately expensive. Another drawback with the prior art mounting structure is that an extra space is needed for fixing the casing to the equipment support, obstructing efficient equipment loading.